Slip assembly for downhole tools

Abstract

A slip assembly for downhole tools comprises a slip ring for engaging a surface of a wellbore and a cone for expanding the slip ring into engagement with the surface of the wellbore. The slip ring has an interior surface defining a trough. The cone has an exterior surface defining a ridge. The ridge is wider than the trough, whereby the slip ring can unbend over a top of the ridge.

What is claimed is: 
     
       1. A slip assembly for downhole tools, comprising:
 a slip ring for engaging a surface of a wellbore, the slip ring having a trough; 
 a cone for expanding the slip ring into engagement with the surface of the wellbore, the cone having a ridge, 
 the ridge being wider than the trough; 
 a crest surface and two flank surfaces defining the ridge, the crest surface being slanted relative to a longitudinal axis of the slip assembly, the two flank surfaces being oriented at a first angle relative to each other; and 
 a crease surface and two side surfaces defining the trough, the crease surface being slanted relative to the longitudinal axis of the slip assembly, the two side surfaces being oriented at a second angle relative to each other, 
 the first angle being greater than the second angle. 
 
     
     
       2. The slip assembly of  claim 1 ,
 the slip ring comprising an interior surface, wherein the interior surface defines the trough; and 
 the cone further comprising an exterior surface, wherein the exterior surface defines the ridge. 
 
     
     
       3. The slip assembly of  claim 1 ,
 the trough having a depth and a span; and 
 the ridge having a height and a base, 
 wherein an aspect ratio of the depth by the span being greater than an aspect ratio of the height by the base. 
 
     
     
       4. The slip assembly of  claim 1  wherein the first angle is obtuse. 
     
     
       5. The slip assembly of  claim 1 , comprising:
 a breakable webbed interface for connecting portions of the slip ring, the breakable webbed interface having an aperture; and 
 a splitting fin protruding from one of the two flank surfaces and at least partially into the aperture, 
 the splitting fin having a bevel surface oriented at a third angle relative to the one of the two flank surfaces, the third angle being obtuse. 
 
     
     
       6. The slip assembly of  claim 1 , comprising:
 a pair of segments at least partially forming the slip ring, 
 the segments of the pair being connected by a flexible webbed interface, 
 the flexible webbed interface being located at a bottom of the trough. 
 
     
     
       7. A slip assembly for downhole tools, comprising:
 a slip ring for engaging a surface of a wellbore, the slip ring having:
 a plurality of segments joined by webbed interfaces, 
 a cylindrical envelope, wherein the cylindrical envelope has a first radius and a first axis; 
 a plurality of outer cylindrical sectors, each cylindrical sector having a second radius and a second axis, 
 wherein each second axis is decentered with respect to the first axis in a direction away from one of the plurality of webbed interfaces and by a recess distance; and 
 
 a cone for expanding the slip ring into engagement with the surface of the wellbore; 
 wherein the cone has an exterior surface, wherein the exterior surface defines a ridge, the ridge having a crest surface and two flank surfaces, the crest surface being slanted relative to a longitudinal axis of the slip assembly, the two flank surfaces being oriented at an obtuse angle relative to each other, 
 a splitting fin protruding from one of the two flank surfaces, the splitting fin having a bevel surface oriented at an obtuse angle relative to the one of the two flank surfaces. 
 
     
     
       8. The slip assembly of  claim 7  wherein each second radius is less than a sum of the first radius and the recess distance. 
     
     
       9. The slip assembly of  claim 7  wherein the one of the plurality of webbed interfaces is a breakable webbed interface having at least one aperture and at least one groove formed therein. 
     
     
       10. The slip assembly of  claim 7  wherein the slip ring has an outer surface having a rounded triangular profile. 
     
     
       11. The slip assembly of  claim 7  wherein the slip ring comprises:
 a pair of segments at least partially forming the slip ring, the segments of the pair being connected by a flexible webbed interface; and 
 a breakable webbed interface for connecting portions of the slip ring, the breakable webbed interface having an aperture. 
 
     
     
       12. The slip assembly of  claim 7 , comprising:
 a trough on an interior surface of the slip ring, 
 the trough having a depth and a span, the ridge having a height and a base, an aspect ratio of the depth by the span being greater than an aspect ratio of the height by the base. 
 
     
     
       13. A method of anchoring downhole tools, comprising:
 providing a slip assembly including a slip ring having a trough for engaging a surface of a wellbore and a cone for expanding the slip ring into engagement with the surface of the wellbore, a crest surface and two flank surfaces defining the ridge, the crest surface being slanted relative to a longitudinal axis of the slip assembly, the two flank surfaces being oriented at a first angle relative to each other; and a crease surface and two side surfaces defining the trough, the crease surface being slanted relative to the longitudinal axis of the slip assembly, the two side surfaces being oriented at a second angle relative to each other, the first angle being greater than the second angle; 
 the slip ring including a pair of segments at least partially forming the slip ring, wherein the segments of the pair are connected by a flexible webbed interface; 
 expanding the slip ring toward the surface of the wellbore with the cone; and 
 unbending the segments of the pair at the flexible webbed interface. 
 
     
     
       14. The method of  claim 13 , wherein the slip ring comprises a breakable webbed interface having a tensile strength lower than the flexible webbed interface, the method further comprising fracturing the breakable webbed interface. 
     
     
       15. The method of  claim 13  wherein the cone comprises a ridge, wherein the ridge is wider than the trough, and wherein the unbending of the segments of the pair comprising the ridge pushing against the trough. 
     
     
       16. The method of  claim 15  further comprising fully contacting a surface of the ridge with a surface of the trough.